MPD: util/ScopeExit.hxx Source File

MPD 0.20.15

ScopeExit.hxx
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1 /*
2 * Copyright (C) 2015 Max Kellermann <max.kellermann@gmail.com>
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 *
8 * - Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 *
11 * - Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the
14 * distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
19 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
20 * FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
22 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
23 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
25 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
26 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
27 * OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
30 #ifndef SCOPE_EXIT_HXX
31 #define SCOPE_EXIT_HXX
32
33 #include "Compiler.h"
34
35 #include <utility>
36
40 template<typename F>
41 class ScopeExitGuard : F {
42 bool enabled = true;
43
44 public:
45 explicit ScopeExitGuard(F &&f):F(std::forward<F>(f)) {}
46
47 ScopeExitGuard(ScopeExitGuard &&src)
48 :F(std::move(src)), enabled(src.enabled) {
49 src.enabled = false;
50 }
51
52 ~ScopeExitGuard() {
53 if (enabled)
54 F::operator()();
55 }
56
57 ScopeExitGuard(const ScopeExitGuard &) = delete;
58 ScopeExitGuard &operator=(const ScopeExitGuard &) = delete;
59 };
60
64 struct ScopeExitTag {
65 /* this operator is a trick so we don't need to close
66 parantheses at the end of the expression AtScopeExit()
67 call */
68 template<typename F>
69 ScopeExitGuard<F> operator+(F &&f) {
70 return ScopeExitGuard<F>(std::forward<F>(f));
71 }
72 };
73
74 #define ScopeExitCat(a, b) a ## b
75 #define ScopeExitName(line) ScopeExitCat(at_scope_exit_, line)
76
87 #define AtScopeExit(...) auto ScopeExitName(__LINE__) = ScopeExitTag() + [__VA_ARGS__]()
88
89 #endif
ScopeExitGuard::operator=
ScopeExitGuard & operator=(const ScopeExitGuard &)=delete
ScopeExitGuard::ScopeExitGuard
ScopeExitGuard(ScopeExitGuard &&src)
Definition: ScopeExit.hxx:47
ScopeExitTag
Internal class.
Definition: ScopeExit.hxx:64
Compiler.h
ScopeExitGuard
Internal class.
Definition: ScopeExit.hxx:41
ScopeExitGuard::ScopeExitGuard
ScopeExitGuard(F &&f)
Definition: ScopeExit.hxx:45
ScopeExitTag::operator+
ScopeExitGuard< F > operator+(F &&f)
Definition: ScopeExit.hxx:69
ScopeExitGuard::~ScopeExitGuard
~ScopeExitGuard()
Definition: ScopeExit.hxx:52